Evaluation of Photoresist Image Adhesion Strength Using the Surface Roughness Factor (SRF) of Copper Substrate

Abstract

Printed circuits are very important for the integration of electronic device fabrication. Each year, finer and more multilayer printed circuits are used. It is necessary to form a finer photoresist pattern before patterning the finer circuits, and several copper subtrate surface treatments are generally used to improve photoresist adhesion strength. However there is no suitable method for estimating adhesion properties of such surfaces. An attempt is made to apply the "surface roughness factor"(SRF, specific surface area of a solid) as a parameter to estimate surface conditions for adhesion. In this study, sultable equipment is made to measure the adhesion strength of the photoresist and the SRF of the copper substrate. It is also, confirmed that the SRF is a good parameter for estimating adhesion properties of surfaces, and there is a quantitative relationship between the adhesion strength of photoresist and SRF of the substrate.